Deep Brain Stimulation Helps Control Parkinson’s Symptoms

A surgical procedure that involves implanting electrodes in the brain is helping some patients with Parkinson’s Disease control their symptoms after their medications stop working.

Parkinson’s patients are usually treated with a variety of drugs to help alleviate the symptoms of the condition, including tremors, stiffness and slowness of movement.

The medications, which do not slow the underlying cause of the disease, the loss of dopamine in the brain, usually become less effective over time. As a result, patients need higher doses. Sometimes, the duration of a single dose doesn’t last as long and patients “freeze up” unexpectedly.

In some cases, the medications cause their own symptoms such as unwanted writhing movements called dyskinesia.

But for a significant number of these patients, around 15 to 20 percent, there is a surgical procedure that can help.

The treatment, called Deep Brain Stimulation (DBS), has been proven to be a highly effective therapy that allows for a greater enjoyment of life.

DBS involves the implantation of electrodes into a specific area of the brain through small holes in the top of the head. The procedure is done in a minimally invasive fashion guided by advanced imaging, computerized navigation and electrical recordings of the brain.

In a second procedure, the electrodes are connected to a pacemaker-like device that is implanted under the chest wall.

In specifically selected patients, the procedure alleviates a number of Parkinson’s symptoms, including tremors, slow movements and muscle stiffness.

“Deep Brain Stimulation has truly revolutionized the treatment of Parkinson’s,” says Dr. Ron Alterman, Chief of Neurosurgery at Beth Israel Deaconess Medical Center, which was the first hospital in New England to offer the procedure. Dr. Alterman has been performing DBS since 1997 and has implanted more than 1,000 DBS devices, among the most ever done in the U.S.

“Deep Brain Stimulation allows us to extend the effectiveness of the Parkinson’s medications and keep patients more highly functional,” he says.

One such patient is Rist Bonnefond, 64, of Fayette, Maine, who was diagnosed with Parkinson’s in 1999. Bonneford was training for a marathon when he started dragging his right foot while running.

“I was in denial for a while, but I finally went to the doctor,” he says. At first, it was thought he had Multiple Sclerosis, but eventually he was diagnosed with Parkinson’s.

He took a drug called Requip for several years, which worked to control his symptoms, including an unnatural gait, stiffness, muscle pain and a feeling of “walking around in a fog” for about four years. “I was able to keep it a secret,” he says.

Over time, however, the drug lost its effectiveness. The now retired school headmaster went on the drug levodopa but that also did not do enough to control the symptoms, so his doctor told him about Deep Brain Stimulation. After thinking about it for a while, he decided to go ahead with it and had the procedure a year ago at BIDMC.

“It helped me immensely,” Bonnefond says. “It has alleviated a lot of my stiffness. I’m more flexible and have reduced pain in my muscles. And I’m not as sore in the morning. Most importantly, I don’t feel like I’m in a fog so much.”

Bonnefond, who remains on levodopa, says he still has some symptoms, such as when walking his body sometimes freezes up while his feet keep on going, and that causes him to fall occasionally.

But, overall, he feels much better. He says he has been told the improvements should last at least five years.

“What lies beyond that, I’m not sure,” he says.

The implanted electrodes deliver high frequency electrical stimulation to areas deep within the brain. The device is kept on at all times and must be replaced every three to five years. The procedure is done on an outpatient basis.

Despite many years of experience with the devices and many studies documenting their effectiveness, doctors still don’t know quite how the treatment works to control the symptoms of the disease.

“This is a hot area of research,” says Dr. Alterman. “If we can figure out how DBS improves the symptoms of PD, we may be able to improve the results further.”

Patients with severe gait imbalance and falls may not improve with DBS, particularly if those symptoms are not improved by medications. According to Dr. Alterman, “If a symptom does not improve with medications, it will also not respond to DBS. The procedure doesn’t replace the medications, it makes them work better.”

In addition, patients who have developed dementia as a result of their advancing Parkinson’s should not undergo the operation as the surgery can make their dementia worse. Patients are typically screened for this during the pre-surgical workup.

Deep Brain Stimulation was developed in France in the late 1980s as a more benign alternative to brain tissue ablation, in which areas of the brain thought to be responsible for abnormal movements are destroyed.

Ablation is more risky because it can cause brain damage or paralysis that is irreversible. “The nice thing about DBS is that we can always shut the device off if there’s a problem,” says Dr. Alterman. “With ablation, what’s done is done.”

Like all surgeries, DBS has its risks, including bleeding, stroke, and infection, but these are rare, according to Dr. Alterman.

He states that other promising therapies to fight Parkinson’s, such as gene therapy and stem cell transplantation, have not worked out so far and few new therapies appear to be on the horizon despite aggressive research efforts. In contrast, a recent study from Europe suggests that Parkinson’s patients may derive greater benefit from the procedure performed even earlier in their disease course.

“Deep Brain Stimulation will be a mainstay of Parkinson’s treatment for a long time to come,” he says.